Asked whether she had evidence of North Korea’s support for international terrorism, Mrs. Clinton said: “We’re just beginning to look at it. I don’t have an answer for you right now.”

Several senators last week wrote President Obama asking him to consider putting North Korea back on the list.

The Bush administration removed North Korea from the list in a bid to revive the faltering six-nation denuclearization talks that have collapsed. North Korea also had promised at the time to dismantle its nuclear weapons facilities but has since refused to follow through.

Coming off the list meant North Korea has been able to better tap into international finance and see some trade sanctions lifted — benefits that would be reversed, although other sanctions have remained as a result of its first nuclear test in 2006.

Mrs. Clinton said she has been in close communication with other countries on how to respond to North Korea’s increasing threat of aggression. She added that one “positive development” of North Korean saber rattling is that it has brought the other members of the six-party process — Japan, South Korea, China, Russia and the United States — closer.

The secretary also said that she was working with foreign ministers and the United Nations on the North Korea issue. Proposed U.N. options include additional economic sanctions and an arms embargo.

“We think we’re going to come out of this with a very strong resolution with teeth that will have consequences for the North Korean regime,” she said.

The administration’s increasingly tough talk against North Korea received an unlikely endorsement from former House Speaker Newt Gingrich, a frequent critic of Democrats.

When asked about the administration’s discussion about placing North Korea back on the terrorist list, the Georgia Republican told CBS’ “Face the Nation” program Sunday that he thought it was a “good step in the right direction.”

“In the long run, we’re going to have to find a strategy that uses diplomatic and economic means to replace the current dictatorship,” he said. “This is an inevitably terrifying dictatorship that is desperately trying to get enough nuclear weapons.”

Mr. Gingrich added that China, which supplies North Korea which much of its food and fuel, must do more to pressure the reclusive country to halt its nuclear program.

“The Chinese can coerce them any morning they want to,” he said, but “the Chinese like them as a way of dividing [North and South] Korea and threatening Japan. No one should kid themselves.”